Felt gas escapes through the magazine well?

Johnny_Boy · 11-03-2009, 07:43 PM

I've shot my 94 clone three times so far at a range with well over total 500 rounds.

Twice, I've felt the heat and pressure of the gas escaping through the mag well. I felt this, since I put my left hand in front of the mag well and the body, when I shoot.

What is causing this? I thought they were squib loads since when this happens the round does not sound right (they don't have the same loud bang). So, I checked the barrel to make sure it is clear both time, and they were clear.

However, I am not sure if the squib would cause the pressure to escape from the chamber? I am assuming that the bolt is moving backwards, while the explosion is happening in the chamber? Maybe issues with the roller not delaying enough? Do I need to lubricate the rollers more? (sorry this is my first roller delayed gun, so I am not sure what to look for)

What about out-of-battery firing? Maybe the bolt didn't quite close from the last cycle and the current round is not completely closed in by the bolt?

I don't remember what brand of ammo it was since I bought like 5 different brands to try out (they were not WWB or Blazer), but I think they were two different brands each time.

swiss_seth · 11-03-2009, 07:47 PM

I would guess a little bit is normal

when I fire my CA94 with a suppressor it shoots smoke out of the mag too, so it would make sense that yours is doing it to a lesser extent

twisted954 · 11-04-2009, 03:31 AM

if you're talking about a ton of smoke you might have issues, but if you are firing rapid, smoke will shoot out the magwell and mag...actually if you dig around, there are a bunch of cool pictures of this effect take by cameras set up for high speed photography...the thing is, the roller guns bleed pressure for a second during the delay via the flutes...for larger caliber guns this is to release the round from the chamber, but for 9mm this is just kind of an extra feature that it is debatable weather or not is is necessary...either way, gas flows backwards via the fluting as a result of the delayed action...so a little puff isn't a big deal...now if the puff is kind of large or seems way disproportionate, then your action is stuck longer than it should be...this could be a result of several things, but if i were you, i would check the bolt gap, inspect the barrel for damage, give everything a good cleaning and if everything looks okay and the gun is running...pay attention but don't worry...you will get used to what is normal or not normal with time.

Johnny_Boy · 11-04-2009, 06:56 AM

It is a small puff. My main concern was around the fact that it does not do this at all 99% of the time, but a couple rounds did this, and the sound of that particular rounds was not normal.

BTW, it is not just light smoke that comes out. The heat also comes out in a form of compressed hot air from the space between the magazine and the mag well.

I will check the head space and see if it is within the spec.

twisted954 · 11-04-2009, 07:07 AM

oh i got you now. You very well might have had underpowered rounds there...sorry for the confusion...I wouldnt worry about bolt gap now, although regularly checking bolt gap is a good idea specially after events, but i would really give that barrel a good once over. If you had an odd fire and then stopped shooting immediately and cleared everything you are most likely good...anyways im sure you knew all that.

Clicker · 11-04-2009, 11:38 AM

My take on this is that the case is not sealing the chamber due to the round being underpowered. With weak ammo the pressure is lower than normal and the case doesn't expand & seal the chamber which allows the gas blowby you're feeling.
The flutes in the chamber form a conduit to vent the gas in this case. The next time it happens if you can find the case that caused the blowby I bet it's got more fouling on it than the normal powered cases.

11-03-2009, 07:43 PM	#1
Johnny_Boy Junior Member Join Date: Aug 2009 Posts: 5	Felt gas escapes through the magazine well? I've shot my 94 clone three times so far at a range with well over total 500 rounds. Twice, I've felt the heat and pressure of the gas escaping through the mag well. I felt this, since I put my left hand in front of the mag well and the body, when I shoot. What is causing this? I thought they were squib loads since when this happens the round does not sound right (they don't have the same loud bang). So, I checked the barrel to make sure it is clear both time, and they were clear. However, I am not sure if the squib would cause the pressure to escape from the chamber? I am assuming that the bolt is moving backwards, while the explosion is happening in the chamber? Maybe issues with the roller not delaying enough? Do I need to lubricate the rollers more? (sorry this is my first roller delayed gun, so I am not sure what to look for) What about out-of-battery firing? Maybe the bolt didn't quite close from the last cycle and the current round is not completely closed in by the bolt? I don't remember what brand of ammo it was since I bought like 5 different brands to try out (they were not WWB or Blazer), but I think they were two different brands each time.

11-03-2009, 07:47 PM	#2
swiss_seth Desperately Needs Treatment Join Date: Jan 2007 Location: Pittsburgh, PA Posts: 1,069	I would guess a little bit is normal when I fire my CA94 with a suppressor it shoots smoke out of the mag too, so it would make sense that yours is doing it to a lesser extent __________________ Got Libertarian? Vouloir, Croire et Oser Veni, vidi, vici Sierra Echo Tango Hector

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11-04-2009, 03:31 AM	#3
twisted954 Gets the Shakes if No HK Contact in 24 Hour Period Join Date: Nov 2007 Posts: 582	if you're talking about a ton of smoke you might have issues, but if you are firing rapid, smoke will shoot out the magwell and mag...actually if you dig around, there are a bunch of cool pictures of this effect take by cameras set up for high speed photography...the thing is, the roller guns bleed pressure for a second during the delay via the flutes...for larger caliber guns this is to release the round from the chamber, but for 9mm this is just kind of an extra feature that it is debatable weather or not is is necessary...either way, gas flows backwards via the fluting as a result of the delayed action...so a little puff isn't a big deal...now if the puff is kind of large or seems way disproportionate, then your action is stuck longer than it should be...this could be a result of several things, but if i were you, i would check the bolt gap, inspect the barrel for damage, give everything a good cleaning and if everything looks okay and the gun is running...pay attention but don't worry...you will get used to what is normal or not normal with time.

11-04-2009, 06:56 AM	#4
Johnny_Boy Junior Member Join Date: Aug 2009 Posts: 5	It is a small puff. My main concern was around the fact that it does not do this at all 99% of the time, but a couple rounds did this, and the sound of that particular rounds was not normal. BTW, it is not just light smoke that comes out. The heat also comes out in a form of compressed hot air from the space between the magazine and the mag well. I will check the head space and see if it is within the spec.

11-04-2009, 07:07 AM	#5
twisted954 Gets the Shakes if No HK Contact in 24 Hour Period Join Date: Nov 2007 Posts: 582	oh i got you now. You very well might have had underpowered rounds there...sorry for the confusion...I wouldnt worry about bolt gap now, although regularly checking bolt gap is a good idea specially after events, but i would really give that barrel a good once over. If you had an odd fire and then stopped shooting immediately and cleared everything you are most likely good...anyways im sure you knew all that.

11-04-2009, 11:38 AM	#6
Clicker Senior Member Join Date: Jan 2008 Location: Coastal SC Age: 51 Posts: 190	My take on this is that the case is not sealing the chamber due to the round being underpowered. With weak ammo the pressure is lower than normal and the case doesn't expand & seal the chamber which allows the gas blowby you're feeling. The flutes in the chamber form a conduit to vent the gas in this case. The next time it happens if you can find the case that caused the blowby I bet it's got more fouling on it than the normal powered cases.